Forecasting adjustment based on Holiday statistics (sum on specific time items)
I have a challenge and I am searching for the best solution. I have (a lot of) sales data and I am using that data to forecast on a daily level for the coming weeks. National holidays have a huge impact on most products the week before and the week after a holiday. I would like that impact to be reflected in the forecast. I can imagine that these kind of activities have been done before (promotions?), any suggestions are welcome!
I started with a new list (Holiday impact days) that counts backwards to -7 before the holiday and count forward to 7 after the holiday. I would then use that list to adjust the forecast before and after holidays.
So in an example:
- Monday 10 June is a Dutch holiday.
- Then Friday 7 June would be 3 days before the Holiday and be mapped to list item -3 of the Holiday impact days.
- The calculation Friday Actual / Friday Average would determine the impact of the 10 June holiday on Friday the 7th.
- The average of impacts of all Holidays on Fridays that are -3 from the Holiday would give me a nice figure on what holidays on Monday mean for the sales on Friday. However I cannot seem to be able to sum over the time dimension on that list (https://community.anaplan.com/t5/Idea-Exchange/Support-aggregation-over-time-dimension/idi-p/35440) Creating a line item that includes time, the 15 day list AND all of the products is not an option due to the size increase. I am not to fond of creating a new day hierarchy simply for this issue either, but it might be my next step.
This is a nice to have, as updating the forecast manually for each holiday is certainly possible; any solution that requires too much size is not an option.
Thanks for taking a look at my case,